Israel is now entering its third strategic environment. The constant threat of state-on-state war defined the first, which lasted from the founding of the Jewish state until its peace treaty with Egypt. A secure periphery defined the second, which lasted until recently and focused on the Palestinian issue, Lebanon and the rise of radical Sunni Islamists. The rise of Iran as a regional power and the need to build international coalitions to contain it define the third.

Israel's fundamental strategic problem is that its national security interests outstrip its national resources, whether industrial, geographic, demographic or economic. During the first phase, it was highly dependent on outside powers -- first the Soviet Union, then France and finally the United States -- in whose interest it was to provide material support to Israel. In the second phase, the threat lessened, leaving Israel relatively free to define its major issues, such as containing the Palestinians and attempting to pacify Lebanon. Its dependence on outside powers decreased, meaning it could disregard those powers from time to time. In the third phase, Israel's dependence on outside powers, particularly the United States, began increasing. With this increase, Israel's freedom for maneuver began declining.

Containing the Palestinians by Managing its Neighbors

The Palestinian issue, of course, has existed since Israel's founding. By itself, this issue does not pose an existential threat to Israel, since the Palestinians cannot threaten the Israeli state's survival. The Palestinians have had the ability to impose a significant cost on the occupation of the West Bank and the containing of the Gaza Strip, however. They have forced the Israelis to control significant hostile populations with costly, ongoing operations and to pay political costs to countries Israel needs to manage its periphery and global interests. The split between Hamas and Fatah reduced the overall threat but raised the political costs. This became apparent during the winter of 2008-2009 during Operation Cast Lead in Gaza when Hamas, for its own reasons, chose to foment conflict with Israel. Israel's response to Hamas' actions cost the Jewish state support in Europe, Turkey and other places.

Ideological or religious considerations aside, the occupation of the territories makes strategic sense in that if Israel withdraws, Hamas might become militarized to the point of threatening Israel with direct attack or artillery and rocket fire. Israel thus sees itself forced into an occupation that carries significant political costs in order to deal with a theoretical military threat. The threat is presently just theoretical, however, because of Israel's management of its strategic relations with its neighboring nation-states.

Israel has based its management of its regional problem less on creating a balance of power in the region than on taking advantage of tensions among its neighbors to prevent them from creating a united military front against Israel. From 1948 until the 1970s, Lebanon refrained from engaging Israel. Meanwhile, Jordan's Hashemite regime had deep-seated tensions with the Palestinians, with Syria and with Nasserite Egypt. In spite of Israeli-Jordanian conflict in 1967, Jordan saw Israel as a guarantor of its national security. Following the 1973 war, Egypt signed a peace treaty with Israel that created a buffer zone in the Sinai Peninsula.

By then, Lebanon had begun to shift its position, less because of any formal government policy and more because of the disintegration of the Lebanese state and the emergence of a Palestine Liberation Organization presence in southern Lebanon. Currently, with Syria in chaos, Jordan dependent on Israel and Egypt still maintaining the treaty with Israel despite recent Islamist political gains, only Lebanon poses a threat, and that threat is minor.

The Palestinians therefore lack the political or military support to challenge Israel. This in turn has meant that other countries' alienation over Israeli policy toward the Palestinians has carried little risk. European countries opposed to Israeli policy are unlikely to take significant action. Because political opposition cannot translate into meaningful action, Israel can afford a higher level of aggressiveness toward the Palestinians.

Thus, Israel's strongest interest is in maintaining divisions among its neighbors and maintaining their disinterest in engaging Israel. In different ways, unrest in Egypt and Syria and Iran's regional emergence pose a serious challenge to this strategy.

Egypt

Egypt is the ultimate threat to Israel. It has a huge population and, as it demonstrated in 1973, it is capable of mounting complex military operations.

But to do what it did in 1973, Egypt needed an outside power with an interest in supplying Egypt with massive weaponry and other support. In 1973, that power was the Soviet Union, but the Egyptians reversed their alliance position to the U.S. camp following that war. Once their primary source of weaponry became the United States, using that weaponry depended heavily on U.S. supplies of spare parts and contractors.

At this point, no foreign power would be capable of, or interested in, supporting the Egyptian military should Cairo experience regime change and a break with the United States. And a breach of the Israeli-Egyptian peace treaty alone would not generate a threat to Israel. The United States would act as a brake on Egyptian military capabilities, and no new source would step in. Even if a new source did emerge, it would take a generation for the Egyptians to become militarily effective using new weapon systems. In the long run, however, Egypt will remain Israel's problem.

Syria

The near-term question is Syria's future. Israel had maintained a complex and not always transparent relationship with the Syrian government. In spite of formal hostilities, the two shared common interests in Lebanon. Israel did not want to manage Lebanon after Israeli failures in the 1980s, but it still wanted Lebanon -- and particularly Hezbollah -- managed. Syria wanted to control Lebanon for political and economic reasons and did not want Israel interfering there. An implicit accommodation was thus possible, one that didn't begin to unravel until the United States forced Syria out of Lebanon, freeing Hezbollah from Syrian controls and setting the stage for the 2006 war.

Israel continued to view the Alawite regime in Syria as preferable to a radical Sunni regime. In the context of the U.S. presence in Iraq, the threat to Israel came from radical Sunni Islamists; Israel's interests lay with whoever opposed them. Today, with the United States out of Iraq and Iran a dominant influence there, the Israelis face a more complex choice. If the regime of President Bashar al Assad survives (with or without al Assad himself), Iran -- which is supplying weapons and advisers to Syria -- will wield much greater influence in Syria. In effect, this would create an Iranian sphere of influence running from western Afghanistan to Iraq, Syria and into Lebanon via Hezbollah. It would create a regional power. And an Iranian regional power would pose severe dangers to Israel.

Accordingly, Israel has shifted its thinking from supporting the al Assad regime to wanting it to depart so that a Sunni government hostile to Iran but not dominated by radical Islamists could emerge. Here we reach the limits of Israeli power, because what happens in Syria is beyond Israel's control. Those who might influence the course of events in Syria apart from Iran include Saudi Arabia and Turkey. Both are being extremely cautious in their actions, however, and neither government is excessively sensitive to U.S. needs. Israel's main ally, the United States, has little influence in Syria, particularly given Russian and, to some extent, Chinese opposition to American efforts to shape Syria's future.

Even more than Egypt, Syria is a present threat to Israel, not by itself but because it could bring a more distant power -- Iran -- to bear. As important, Syria could threaten the stability of the region by reshaping the politics of Lebanon or destabilizing Jordan. The only positive dimension for Israel is that Iran's military probably will not be able to deploy significant forces far from its borders for many years. Iran simply lacks the logistical or command capabilities for such an operation. But developing them is just a matter of time. Israel could, of course, launch a war in Syria. But the challenge of occupying Syria would dwarf the challenge Israel faces with the Palestinians. On the other side of the equation, an Iranian presence in Syria could reshape the West Bank in spite of Shiite-Sunni tensions.

The United States and the Europeans, with Libya as a model, theoretically could step into managing Syria. But Libya was a seven-month war in a much less populous country. It is unlikely they would attempt this in Syria, and if they did, it would not be because Israel needed them to do so. And this points to Israel's core strategic weakness. In dealing with Syria and the emergent Iranian influence there, Israel is incapable of managing the situation by itself. It must have outside powers intervening on its behalf. And that intervention poses military and political challenges that Israel's patron, the United States, doesn't want to undertake.

It is important to understand that Israel, after a long period in which it was able to manage its national security issues, is now re-entering the phase where it cannot do so without outside support. This is where its policy on the Palestinians begins to hurt, particularly in Europe, where intervention on behalf of Israeli interests would conflict with domestic European political forces. In the United States, where the Israeli-Palestinian problem has less impact, the appetite to intervene in yet another Muslim country is simply not there, particularly without European allies.

Iran

This is all compounded by the question of Iranian nuclear weapons. In our view, as we have said, the Iranians are far closer to a controlled underground test than to a deliverable weapon. Israel's problem is that Iran appears on the verge of a strategic realignment in the region. The sense that Iran is an emerging nuclear power both enhances Iran's position and decreases anyone's appetite to do anything about it. Israel is practicing psychological warfare against Iran, but it still faces a serious problem: The more Iran consolidates its position in the Middle East and the closer it is to a weapon the more other countries outside the region will have to accommodate themselves to Iran. And this leaves Israel vulnerable.

Israel cannot do much about Syria, but a successful attack on Iranian nuclear facilities could undermine Iranian credibility at a time when Israel badly needs to do just that. Here again, Israel faces its strategic problem. It might be able to carry out an effective strike against Iran, particularly if, as has been speculated, a country such as Azerbaijan provides facilities like airfields. However, even with such assistance, Israel's air force is relatively small, meaning there is no certainty of success. Nor could Israel strike without American knowledge and approval. The Americans will know about an Israeli strike by technical intelligence. Hiding such a strike from either the Americans or Russians would be difficult, compounding the danger to Israel.

More important, Israel cannot strike Iran without U.S. permission because Israel cannot guarantee that the Iranians would not mine the Strait of Hormuz. Only the United States could hope to stop the Iranians from doing so, and the United States would need to initiate the conflict by taking out the Iranian mine-laying capability before the first Israeli strike. Given its dependence on the United States for managing its national security, the decision to attack would have to be taken jointly. An uncoordinated attack by Israel would be possible only if Israel were willing to be the cause of global economic chaos.

Israel's strategic problem is that it must align its strategy with the United States and with anyone the United States regards as essential to its national security, such as the Saudis. But the United States has interests beyond Israel, so Israel is constantly entangled with its patron's multiplicity of interests. This limits its range of action as severely as its air force's constraints do.

Since its peace treaty with Egypt, Israeli dependence on outsiders was limited. Israel could act on issues like settlements, for example, regardless of American views. That period is coming to an end, and with it the period in which Israel could afford to deviate from its patron. People frequently discuss any U.S.-Israeli rift in terms of personal relations between U.S. President Barack Obama and Israeli Prime Minister Benjamin Netanyahu, but this is mistaken. It is uncertainty in Egypt and Syria and the emergence of Iran that have created a new strategic reality for Israel.